Controllable pressure-reducing valve and device for the generation of pressure change signals

Abstract

A controllable pressure reducing valve has a housing which includes an inner chamber extending in the direction of a longitudinal axis and an inlet opening and an outlet opening. The inlet opening and the outlet opening open into the inner chamber at an axial relative distance. The inner chamber includes between the mouths of the inlet opening and the outlet opening at least one annular wall having a cylindrical valve bore. An axially movable valve body which is arranged in the inner chamber, extends through the valve bore and has a piston-type portion guided in the valve bore and adapted to close the valve bore. The piston-type portion includes at least one control recess bounded by a control step which extends in axial direction and in circumferential direction and combines with an edge of the valve bore to form a controllable valve opening.

1. A controllable pressure reducing valve for reducing the pressure of fluids, having a housing which includes an inner chamber extending in the direction of a longitudinal axis and having an inlet opening, downstream of the inlet opening at least one adjustable first pressure reducing stage, and downstream of the first pressure reducing stage a first outlet opening, wherein the inner chamber of the housing accommodates at least one adjustable second pressure reducing stage arranged parallel to the first outlet opening and downstream of the first pressure reducing stage, and wherein downstream of the second pressure reducing stage a second outlet opening is arranged, and both outlet openings are adapted to be closed independently of each other. 
     
     
       2. The pressure reducing valve according to  claim 1 , wherein at least one adjustable pressure reducing stage is formed by at least one annular wall arranged in the housing and having a cylindrical valve bore and an axially movable valve body which is arranged in the inner chamber, extends through the valve bore and has a piston-type portion guided in the valve bore and including a control recess combining with an edge of the valve bore to form a controllable valve opening. 
     
     
       3. The pressure reducing valve according to  claim 2 , wherein the piston-type portion includes two control recesses, said control recesses lying side-by-side in circumferential direction and being arranged symmetrical about the axis. 
     
     
       4. The pressure reducing valve according to  claim 2 , wherein the control recess is bounded by a control step extending in axial direction and in circumferential direction, said control step being configured such that the valve opening obtained has a compact cross-section of orifice. 
     
     
       5. The pressure reducing valve according to  claim 4 , wherein the control step has two diverging portions which are symmetrical in relation to a plane of symmetry containing the longitudinal axis and converge in the plane of symmetry. 
     
     
       6. The pressure reducing valve according to  claim 4 , wherein the control step includes a portion which, when developed, corresponds to the curve shape of a sine function or an exponential function. 
     
     
       7. The pressure reducing valve according to  claim 2 , wherein the piston-type portion of the valve body is guided in the valve body along the entire length of its control stroke. 
     
     
       8. The pressure reducing valve according to  claim 2 , wherein a conical surface adjoins an edge of the cylindrical valve bore. 
     
     
       9. The pressure reducing valve according to  claim 1 , wherein the housing is composed of first and second annular housing portions, and wherein the first annular housing portion includes an annular wall with cylindrical valve bore and the second annular housing portion includes a radial port. 
     
     
       10. The pressure reducing valve according to  claim 9 , wherein the annular wall with the cylindrical valve bore is constructed as a separate insert and is arranged between two annular housing portions. 
     
     
       11. The pressure reducing valve according to  claim 9 , wherein the annular housing portions are arranged between end plates which are connected to one another by rod-shaped elements. 
     
     
       12. The pressure reducing valve according to  claim 2 , wherein the valve body has a longitudinal bore which is connected to the inlet opening of the housing. 
     
     
       13. The pressure reducing valve according to  claim 2 , wherein the valve body is pressure balanced in axial direction. 
     
     
       14. The pressure reducing valve according to  claim 2 , wherein the valve body includes a valve spindle and valve sleeves attached to the valve spindle, with each of the valve sleeves forming a piston-type portion. 
     
     
       15. The pressure reducing valve according to  claim 14 , wherein the valve sleeves are made of a wear resistant material. 
     
     
       16. A device for the generation of pressure change signals, which are adapted to be transmitted to a downhole location, in a mud pump supply conduit connected to drill pipes by use of a controllable pressure reducing valve having a housing which includes an inner chamber extending in the direction of a longitudinal axis, an inlet opening, downstream of the inlet opening at least one adjustable first pressure reducing stage, and downstream of the first pressure reducing stage a first outlet opening, wherein the inner chamber of the housing accommodates at least one adjustable second pressure reducing stage, wherein the second pressure reducing stage is connected downstream of the first pressure reducing stage parallel to the first outlet opening, and that downstream of the second pressure reducing stage a second outlet opening is arranged, wherein both outlet openings are adapted to be closed independently of each other, and wherein the inlet opening of the pressure reducing valve is connected to a bypass conduit branching off the supply conduit, and optionally one of said outlet openings is connected to a mud conduit leading to a mud pit. 
     
     
       17. The device according to  claim 16 , wherein the valve body is movable by a travel-controlled actuator. 
     
     
       18. The device according to  claim 17 , wherein control of the actuator is performed by an electropneumatic positioner. 
     
     
       19. The device according to  claim 16 , comprising a pressure reducing valve wherein at least one adjustable pressure reducing stage is formed by at least one annular wall arranged in the housing and having a cylindrical valve bore and an axially movable valve body which is arranged in the inner chamber, extends through the valve bore and has a piston-type portion guided in the valve bore and including a control recess combining with an edge of the valve bore to form a controllable valve opening. 
     
     
       20. The device according to  claim 19 , wherein the piston-type portion includes two control recesses, said control recesses lying side-by-side in circumferential direction and being arranged symmetrical about the axis. 
     
     
       21. The device according to  claim 19 , wherein the control recess is bounded by a control step extending in axial direction and in circumferential direction, said control step being configured such that the valve opening obtained has a compact cross-section of orifice. 
     
     
       22. The device according to  claim 20 , wherein the control step has two diverging portions which are symmetrical in relation to a plane of symmetry containing the longitudinal axis and converge in the plane of symmetry. 
     
     
       23. The device according to  claim 20 , wherein the control step includes a portion which, when developed, corresponds to the curve shape of a sine function or an exponential function. 
     
     
       24. The device according to  claim 19 , wherein the piston-type portion of the valve body is guided in the valve body along the entire length of its control stroke. 
     
     
       25. The device according to  claim 19 , wherein a conical surface adjoins an edge of the cylindrical valve bore. 
     
     
       26. The device according to  claim 19 , wherein the valve body has a longitudinal bore which is connected to the inlet opening of the housing. 
     
     
       27. The device according to  claim 19 , wherein the valve body is pressure balanced in axial direction. 
     
     
       28. The device according to  claim 19 , wherein the valve body includes a valve spindle and valve sleeves attached to the valve spindle, with each of the valve sleeves forming a piston-type portion. 
     
     
       29. The device according to  claim 28 , wherein the valve sleeves are made of a wear resistant material. 
     
     
       30. The device according to  claim 16 , wherein the housing is composed of first and second annular housing portions, and wherein the first annular housing portion includes an annular wall with cylindrical valve bore and the second annular housing portion includes a radial port. 
     
     
       31. The device according to  claim 30 , wherein the annular wall with the cylindrical valve bore is constructed as a separate insert and is arranged between two annular housing portions. 
     
     
       32. The device according to  claim 30 , wherein the annular housing portions are arranged between end plates which are connected to one another by rod-shaped elements.